This study investigates (1) how fluctuations in parenting during middle school, which we term parenting lability, relate to youth substance use and other risky behaviors and (2) parent and child characteristics that predict more lability in parenting. Discovering the risk and protective factors for early adolescent substance use is critical because youth who begin using substances during the middle school period face a high risk of developing lifetime alcohol disorders. Parents play a key role in development of early adolescent substance use. Yet, there are important gaps in our knowledge. Most longitudinal studies have focused on how levels and long-term trends in parenting relate to youth outcomes. However, parenting may fluctuate: some families may experience many ups and downs in parenting during middle school, whereas other families may experience predictable trends over time. Yet, we know little about how parenting behaviors fluctuate during middle school and the implications of parenting fluctuations for youth substance use. Our preliminary study suggests that fluctuations in parental knowledge of youth activities are associated with higher levels of youth substance use, even when controlling for mean levels and linear trends in knowledge. The proposed study extends this work to a broader range of constructs: fluctuations in the parent-child affective relationship and parental control may play important roles in preventing substance use but have not yet been studied. We also know little about parent and child characteristics that may be linked to more fluctuations in parenting. This project seeks to fill these gaps. Aim 1 tests if lability in parenting and parent-child relationships during middle schoo (Grades 6-8) predict adolescent substance use in Grade 9, and if these links are moderated by youth gender. Aim 1 investigates if fluctuations in parenting relate to youth substance use and other risky behaviors, above and beyond levels and long-term trends. Aim 2 identifies the parent and child characteristics predict higher lability in parenting during the child's middle school years. Aim 2 tests if parent characteristics (e.g., depression, anxiety, substance use, marital conflict, self-efficacy, social support) and child characteristics (e.g., youth substance use initiation, delinquency, internalizing problems) predict lability in parenting. These aims will be accomplished using data from the PROSPER project (Promoting School- Community-University Partnerships to Enhance Resilience). Innovation: Recent methodological advances now make it possible to capture lability and to explore its impact on development: This study is among the first to apply these advances to study parenting. This study focuses on rural youth, and leverages both survey and observational data to understand this at-risk but understudied population. Public Health Impact: This study will inform prevention efforts by revealing how lability in parenting affects early adolescent substance use and other risky behaviors. Knowledge from this study will provide information crucial to the development of new intervention components designed to help parents reduce lability in parenting over time.